Electric valve translating apparatus



NV 30,1943.` c. c. HERSKIND 2,335,673

ELECTRIC VALVE TRANSLATING APPARATUS Filed Dec. 24, 1940 byje/ His Attorney.

Patented Nov. 30, 1943 ELECTRIC VALVE TRANSLATING APPARATUS Carl C. Hcrskind, Schenectady, N. Y., assignor to General Eiectric Company,

N ew York a corporation of Application December 24, 1940, Serial No. 371,559 6 Claims. (Cl. 175-363) My invention relates to electric Valve translatine apparatus, and more particularly to improved control circuits for translating apparatus of this character.

In electric valve translating systerns including a pluraiity or" electric discharge paths in parallel there is a 'tendency for certain of the discharge to conduct more than their proportionate share of the load current. This 'tendency to be cumulative and to result in poor utilization or the equipment, poor wave in alternating current circuits and poor overall operation of the system. Arrangements have been provided for maintaining toad division tetue.:- parallel operating discharge paths substantially i" accordance with the rating of the discharge paths by controlling excitation ci tne control electrodes associated therewith. ln arrangement of this type employing saturfihie inductive devices interconnected by an ng is described and claimed in my .?atent lated June 17, i941, and assigned the assignee oi the present invention. in accordance 'with the teachings of invention w on improved control circuit for i ision between plurality of discharge oaths also an .ent maintaining a desired citron of the output of cuit .regardncunt oi control used to maintain i u.

i to provide for main.- lity parci" nry ini/en y. control circu 1:aetw-een a @lui fio discharge ooject of f roved control circuit for inail/1- oi cad Toets/een. l

e oaths "which does complicated as the number or diss to controlled increases.

i eject of .my invention to prol unproved control circuifor elecslitting apparatus which maintains a desired division of .load between parallel operating echi-tree oaths and also a desired electrical condition or, the load circuit energized by the valve translating apparatus which is characterized by simplicity and effective operation.

In accordance with an illustrated embodiment of my invention a 'twelve-phase electric valvel translating interconnectsan alternating an increase in the direct current current circuit and a direct current circuit and includes two six-phase rectifier units in parallel. .Each of .the discharge paths of the rectifier tanks, or units, is provided with a control electrode which is energized oy means of suitable excitation or peaking transformers with periodic potentials of peaked wave forro .having the periodicity of the alternating current circuit. The peaking, or impulse transformers are provided With direct current control windings. One of the control windings is energized in accordance with the current transmitted the particular rectiiier unit with which it is associated through means including current transformers and a plurality oi unil terally conducting devices. The control windings thus energized `are effective to retard automatically the phase of the peaked potentials impressed on the controi inercloers es the current transmitted by we discharge paths increases. En order to maintain desired output current of the parallel oper units a second control winding Y the peaking transformers and ener direct current circuit having a cota cnt upon the magnitude of the l These coils are arranged in such tends to advance the bese, ci tn tentials. In this manner out istie such as the output current o system may be made to rei etant and independent oi the in phase produced by the first cont :1E in response to the current conducted c, dvidual units. With this system the regulation. curve of each unit is scene;1 j inherent voltage regulation curve so that te ency tor one rectiiier unit to talee share of the load reduced to a at the saine time the regulating sy tive to compensate for this control i. load division so that a desired voltage or current ci the load circuit may maintained. I:this provides for the ro alleling of the rectifier Without sacrifice all characteristics of 'power output an factor on the alternating current side.

My invention will be better understood oy refoperating and I3 are preferably of the type employing an ionizable medium such as a gas or vapor, and each comprises a plurality of anodes I5, a cathode of conducting liquid lia, and a plurality of control members or grids I6, each associated with one of the anodes. While converting units comprising a plurality of anodes and associated control members with a single cathode have been illustrated, it will be apparent to those skilled in the art that any other type of discharge valves well known in the art may be employed. The transformer I4 includes a Y-connected primary winding I1, associated Y-connected secondary windings I8 and I9. and a1 delta-connected primary winding 20 and associated Y-connected secondary windings 2l and 22. The end terminals ofthe secondary windings I8 and i9 are connected with the anodes I5 of converting unit l2, while the end terminals of the windings 2| and 22 are connected with' the anodes of the converting unit I3. The neutrals of the -Y-con- ,nected windings I8 and I9 are interconnected by a phase equalizing inductive winding or interphase transformer 23 and the Y-connected windings 2l and 22 are connected by Aan interphase transformer 24. The mldpoints of interphase transformers 23 and 24 are connected to the end terminals of an interphase transformer 25, the midpoint of which is connected to the negative line of the direct current circuit II. The cathodes Ita of converting units I2 and I3 are connected together and to the positive line of the direct current circuit II. As iswell understood by those skilled in the art, the network just described, including the transformer secondary windings and the interphase transformer windings, is effective to provide twelve-phase operation of the converting -units I2 and .I3.

The discharge paths of the converting units I2 and I3 are rendered conductive periodically by means of a control circuit which impresses periodic potentials of peaked wave form thereon. Since thecontrol circuits for units I2 and I3 are substantially identical, only one has been. illustrated in detail. The control circuit includes a supply of alternating control voltage 26 having the frequency of the 'supply circuit I0 which is preferably derived from the alternating current supply circuit through insulating transformers (not shown). A master phase shifter 21 energized from the supply of control potential 26 energizes a control bus 28 from which auxiliary 29 and 30 and the excitation cirphase shifters cuits associated with units I2 and I3 are enerof phase shifter gized. The three-phase output 29 is impressed on the delta-connected primary windingsX3I of excitation transformers 32 to 31 The construction of one of the six excitation transformers is shown in more detail in Fig. 2.. Referring now to Fig. 2, each ofthe transformers includes a core structure 38 having a saturable leg 39 on which is wound a secondary inclusive.

.of each`secondary winding 40 of the transformers 32 to 31 inclusive is connected to one terminal of a biasing battery 43, the other terminal of which is connected to the cathode of the converting unit I2. The end terminal of each of the transformer secondary windings is connected with one of the y control members of the unit l2 through a circuit including a current limiting resistor 64 and an additional resistor which is shunted by a unilaterally conductive device 46 poled in a direction to conduct positive grid current. .As illus-- trated in the drawing, the end terminals of the transformer secondary windings of transformers 32 and 33 are connected with control members associated with anodes arranged to conduct at intervals displaced by 180 electrical degrees. Capacitors 41 are connected across the primary windings 3I of the transformers@ to 31 to compensate for the lagging power factor current drawn by the excitation transformers and reduce the volt-ampere rating required in the phase Shifters 21, 29 and 30.

The control windings 42 of excitation transformers 32 to 31 are connected in series and energized from a source of direct current potential which varies in magnitude with the magnitude of the current conducted by the converting unit I2. The polarity of the direct current potential energizing these windings is such as to retard the phase of the excitation potentials induced in the secondary windings 40 as the currentconducted by the unit I2 increases. The eect of this control may be considered as increasing the slope of the regulation curve of the individual converter unit and in this way minimizes the tendency of the unit to take more than its share of the load when operated in parallel with another unit such -asunit i3.

devices 59 and a filter circuit including a reactor 5I and capacitor 52. i This filter serves to smooth out the pulsating direct current output of the y current transformers and unilateral conducting devices 50. Resistors 53 are connected across the current transformers to provide a path for the magnetizing current of the transformer during the half cycles that the anodes with which they are associated are nonconductive. It will be understood that an excitation circuit similar to that just described in connection with converting unit I2 is provided for converting unit I3 so that the excitation potentials appued to the control members of unit I3 are -also retarded in winding 40 and a pair of direct current control u .phase automatically as the current conducted thereby increases. Although in the illustrated embodiment applicantis invention is shown as applied to two separate converting units, it may be readily utilized to balance the current conducted by any number of parallel operating discharge paths, such for example, as the discharge paths associated with the two Y-connected wind- 2,385,678 ings connected with each of the converting units i2 and I3.

The arrangement just described for forcing division of load between converting units l2 and I3 bylretarding the phase of the excitation poa tentials applied to the control members of each unit as the current conducted thereby increases tends to give the converting apparatus very poor regulation and accordingly I provide means for automatically varying the phase of the excitation potentials applied to the control membersof all oi the discharge paths of the converting units I2 and I3 in accordancewith an electrical condition o'f the load circuit Il. The control windings 4I of excitation transformers 32 to 31 are all con- 3 members of ali or the discharge paths. When the current in the direct current circuit falls below a predetermined value the movable element 63 of relay 5B operates to energize the other iield winding section I5 and causes the direct current l motor torrotate in the opposite direction and denected in series through a current limiting resistor 54 to a bus 55 which provides a source of direct current potential variable in response to an electrical condition of the output circuit II. In the arrangement shown, the bus 55 is energized from a direct current source 56 through a variable resistor 51 which is controlled in accordance with the current of the direct current circuit II by a current regulating relay means 58 and a. reversible direct current motor 59. Thev actuating coil 60 of the current regulating relay 58 is energized by the potential across a resistor 6I connected in series with the direct current load circuit. The movable contact 63 of the relay 58 engages xed contacts associated with different field winding sections 64 and 65 of the direct current motor 59 to energize the motor for operation in opposite directions from a source of direct current voltage which may be the source 56.

In the operation of the system just described, the discharge paths of the converting units I2 and I3 operate in parallel and with the transformer arrangement illustrated operate as a twelve-phase rectier system for transmitting energy from the alternating current circuit I0 to the direct current circuit II. The discharge paths are normally rendered nonconductive by the control members I6 energized by the negative biasing battery 43 and are sequentially rendered conductive by periodic potentials of peaked wave form impressed thereon by the secondary Windings 4U of the excitation transformers. As is well understood by those skilled in the art, the output voltage or the output current of the rectiiier system may be controlled by controlling the time in the anode-cathode voltage wave of each of the discharge paths that the discharge path is rendered conductive. In accordance with the pres; ent invention the moment of initiation of discharge of each of the discharge paths is retarded as the current conducted by the discharge path increases. This arrangement serves to minimize the tendency of any of the parallel paths to carry more than their share of the loa-d. With this control alone, the voltage regulation of the direct current circuit is very poor and in order to maintain a desired output voltage or in. the embodiment illustrated a desired output current, the control windings 4I are energized by a variable direct current voltage under the control of a regulating relay means 58. When the current in the direct current circuit II is above that desired the movable element 63 of relay 58 is operated to complete a circuit through iield winding section 64 of motor 59 to operate the same in a direction to increase the portion of the variable resistance 51 included in circuit with the direct current source 56. This reduces the current through the control windings 4I and results in retarding the phase of the potentials impressed on the control f peaked wave crease the resistance in circuit with the control windings 4I. This results in an advance in phase o1' the potentials impressed upon the control members of all of the discharge paths and restores the desired load current in the direct current circuit.

From the foregoing description it is apparent that the present invention provides means for maintaining load division as well as a predetermined characteristic of the output circuit which is simple and which oirers definite advantages Iover those arrangements for maintaining a division of load requiring means for comparing the currents conducted by the parallel paths with each other to obtain a resultant voltage or magnetomotive force by a comparison network which becomes more and more complicated as the number of parallel paths to be controlled increases.

While I have shown and described a particular embodiment of my invention, it will be obvious to those skilled in the art that changes and modications may be made Without departing from my invention, and I, therefore, aim in the appended claims to cover all such changes and modications as fall within the true spirit and scope of my invention. B

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a supply circuit, a load circuit, electric translating apparatus interconnecting said circuits and including a pair of parallel electric discharge paths, a control electrode for controlling the initiation of discharge in each of said parallel discharge paths, a control circuit for controlling the energization of said control electrodes including saturable transformer means -associa-ted with each of said control electrodes for .impressing periodic potentials of form thereon, each of said transformer means including a primary Winding, a secondary Winding associated with a control electrode and a pair of direct current control windings, means for energizing said primary winding with a periodic voltage, means for energizing one of the control windings of each of said transformer means in response to the current conducted by the discharge path controlled by the control electrode with which the transformer means is associated, means for energizing the other control winding of all said transformer means in accordance with an electrical condition of one of the circuits interconnected by said electric translating apparatus, the unidirectional magnetomotive forces produced by said control windings being opposed so that the phase of the periodic potentials impressed on said control members is shifted in accordance with the relaprimary winding, a secondary winding associated' ing one oi the control windings'of each otsaid transformer means in' accordance with the cur-v y' y l i the voltage impressed across said' anode audv cathode, the magnetomotive'force produced by rent conducted by-one of saidV groups of electric discharge pathaand means for energizing'` the' other control Winding of each of said transformer means in accordance with an electrical conditiom of said direct current circuit.

3. In combination, asupply circuit, a load circuit, electric translating apparatus interconnecting said circuits and including a pair of electric discharge paths connected inv parallel, a controly electrode for controlling the initiation of discharge in each of said parallel discharge paths, a i

control circuit for controlling the energization of said control electrodes including transformer means associated with each of said control elec-` trodes for impressing thereon periodic potentials of peaked wave form and each including a primary winding, a secondary winding and a pair of direct current control windings, means for supplying a periodic Voltage to said primary winding,

means connecting said secondary winding withone of said control electrodes, means responsivev to the current transmitted by one of said discharge paths Jfor energizing one of said directcurrent windings for retarding automatically the phase of the potential applied to 'the control electrode associated therewith as the current of said one discharge path. increases, and means for energizing the other of said direct current windings in accordance with an electrical condition of said load circuit to maintain a predetermined charac- A teristic of 'said electrical condition.

4. In combination, a supply circuit, a load cir cuit, at least one of said circuits being an alternating current circuit, a plurality of translating devices interposedv in parallel relation between said circuits 'for transmitting energy therebetween and including at least one electric valve means having an anode, a cathode and a control member, means for effecting a predetermined distribution of load between said translating devices comprising a saturable-inductive device including a core member, a rst control winding, means for energizing said rst control winding in response to the current conducted by said .electric valve means to impress a-unidirectional magnetmotive force on said core member,

a second control winding, means for energizing said second control winding to impress a unidi-.

rectional magnetomotive force on said core y member in opposition to the magnetomotiveV force produced by said first control winding and,

which varies in accordance with an electricalA condition of said load circuit, a primary winding,

means for energizing said primary windin'gwith.

a periodic voltage, and a secondary winding responsive to a magnetic condition of said corey member for impressing on said control member impressed on said control electrode.

lating: devices interposed' in parallel relation betweenv saidA circuits for transmitting energy therebetween and including at least one electric valve means having an anode, a cathode and a control means, and means for eecting a pre'- determined distribution of Aload between said electric valve means and the other of said translating devicesv comprising 'asaturable inductivedevice including a core member, a wind- `ing for impressing on said core member an alternating magnetomotive force, acontrol vwind-- ing for impressing on said core member a unidirectional magnetomotive force which varies in accordance with the current transmitted by said electric valve means, a second control Winding for impressing on said core member a second unidirectional magnetomotiveforce which opposes said ilrstmentioned magnetomotive force and which varies in accordance with an electrical condition of said load circuit, and a winding responsive to a magnetic condition of said core member for impressing on said control means an alternating current voltage variable in phase relative to the voltage impressed across said an'- ode and cathode.

6. An alternating current circuit, a direct cur-Y rent circuit, electric translating apparatus interconnecting said circuits and including a'pair of parallel electric discharge paths, acontrol elec--l trode associated with each ofsaid discharge paths for controlling-the initiation of discharge therein, a control circuit for energizing said l control electrodes to maintain a predetermined' division of load betweenlsaid parallel operating discharge paths including saturable transformer means associated with each of said control electrodes and including 'a primary winding, a secondary winding associated with' one of said control electrodes and a direct current control winding, means for energizing said primary winding with a periodic voltage,` means for energizing said direct current Winding in accordance with the current conducted by the discharge path controlled by the control electrode with which said transformer means is associated to impress a unidirectional magnetomotive force on said transformer means in a direction to retard the phase of the potential impressed on the control electrode energized therefrom as'- the current 

